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Volkswagen warned Friday of production delays at factories in China and other locations after an unexpectedly strong rebound in car sales during the pandemic created a worldwide shortage of semiconductors used in automobiles.

Modern automobiles are heavily computerized, and they require semiconductors for engine controls, automatic braking systems and many other applications.

Semiconductors are at the heart of the high-performance computer chips that power electronic devices like computers and mobile phones, gadgets whose demand has grown as pandemic-induced lockdowns keep people inside their homes.

After the pandemic gutted auto sales earlier this year, many semiconductor makers shifted production to consumer products, Volkswagen said.

But then car sales bounced back faster than expected, especially in China, the world’s largest car market. Semiconductor makers have not been able to meet demand and will take several months to realign production.

As a result, Volkswagen said, it would have to adjust production at factories in China, Europe and North America. Volkswagen has factories in Chattanooga, Tenn., and Puebla, Mexico.

The shortage of parts will mostly affect smaller and midsize cars sold by Volkswagen and the company’s SEAT and Skoda units. Some Audi cars will also be affected, Volkswagen said.

Infineon, one of the largest suppliers of semiconductors to the auto industry, said in a statement that it could not comment on individual customers. But the company said it was planning to step up investment in new production capacity in 2021 to as much as 1.5 billion euros, or $1.8 billion, compared with €1.1bn in 2020.

Automobile sales in most regions are still far below 2019 levels, but the decline has not been as severe as it first appeared.

In Europe, new car registrations plunged more than 75 percent in April compared with a year earlier. For the first 11 months of 2020, registrations were 26 percent below last year’s level, according to the European Automobile Manufacturers Association.

WASHINGTON — The Trump administration imposed greater restrictions on dozens of Chinese companies on Friday, including Semiconductor Manufacturing International Corporation, citing national security concerns with the companies’ ties to the Chinese military.

The U.S. Commerce Department’s order restricts S.M.I.C.’s ability to import tools used to produce its chip, putting the company on a so-called entity list intended to starve foreign companies of U.S.-sourced goods and services. The agency announced a total of 77 foreign entities that are subject to the restrictions, the majority from China.

The dronemaker DJI was also included on the list because of the technology’s alleged connection to China’s human rights abuses, such as spying on ethnic minorities in China.

“Between S.M.I.C.’s relationships of concern with the military industrial complex, China’s aggressive application of military civil fusion mandates and state-directed subsidies, S.M.I.C. perfectly illustrates the risks of China’s leverage of U.S. technology to support its military modernization,” said Commerce Secretary Wilbur Ross.

The order is part of President Trump’s ongoing offensive against Chinese companies, which the administration has accused of posing a national security threat. The administration has focused in particular on technology transfers between the two nations, saying China is trying to use American technology to gain an economic and military advantage.

The Trump administration has penalized dozens of Chinese companies in previous months by adding them to the so-called entity list over national security concerns related to advanced technology, including the telecom giants Huawei and ZTE. It has also added a growing number of companies accused of human rights violations against Muslim minorities in the Xinjiang region to the list, along with companies accused of helping China’s encroachment in the South China Sea, which stretches south of Hong Kong and borders the Philippines, Vietnam, Malaysia and other countries.

About one-third to one-half of S.M.I.C.’s semiconductor tool purchases come from the United States, according to one U.S.-based semiconductor industry expert. But the Commerce order was written narrowly, the person said, and may affect only a small slice of those imports.

The Commerce Department said that S.M.I.C. was targeted because its advanced semiconductors were being used by companies to support the Chinese military’s creation of short-range and ballistic missiles and military aircraft.

Lee R. Raymond, who served…